The invention relates to an apparatus for forming a thread-reserve winding on a bobbin tube with a bobbin plate which rotates together with the bobbin tube. The bobbin plate engages a centering shoulder in the inside diameter of the bobbin tube and has a thread-catching device. The invention further relates to the process for forming a thread-reserve winding as disclosed and described herein.
In a known apparatus of the type mentioned above (European Preliminary Publication No. 69,205, now the same as corresponding U.S. Pat. No. 4,501,116), the bobbin tube is received between two bobbin plates mounted rotatively in the bobbin arms. For centering the bobbin tube, the bobbin plates conventionally have at least one inner shoulder engaging into the inside diameter of the bobbin tube. Also, one of the bobbin plates rotating together with the bobbin tube is provided with a thread-catching device in order, after the bobbin has been changed, to transfer the thread to the inserted empty tube, where some reserve turns are first formed before the actual winding of the bobbin takes place.
Since the bobbin change should take place without an interruption in the spinning operation of the open-end spinning machine, there is also a thread-suction device which receives the continuously supplied thread after an interruption in the spooling operation when the full bobbin is ejected, until the empty tube has been inserted and the thread can be transferred to this. To transfer the thread to the spooling device, the thread-suction device receiving the spun thread has assigned to it a thread guide, the function of which is, on the one hand, to bring the thread together with the suction device into the region of the thread-catching device and, on the other hand, after the reserve winding has been formed, to transfer the thread to the transversing thread guide in order to wind onto the bobbin. After being secured in the thread-catching device, the thread is cut off by a thread-severing device preferably assigned to the thread-suction device.
However, in this method of thread feeding, it has been shown that the method of feeding the thread for the thread-catching device results in relatively long thread ends which are thrown around during the winding of the bobbin and, consequently, not only do they become frayed and useless for subsequent piecing to the preceding bobbin during further processing, but also the reserve winding is loosened, so that it falls off from the tube and is, therefore, wasted.